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AC TIG Puddle Won't Form

11-13-2018, 11:02 AM

I have inconsistent results establishing a puddle for AC TIG on aluminum using a Syncrowave 250. I have tried the following to remedy the problem:
* New tungsten
* Torch angle and rotating tungsten to redirect arc
* Different sized cups
* Adjusting HF dial
* Cranking up the amps
* Brushing and acetone wiping base metal and filler
* AC balance ranging from 6-8 (3=balanced, and balls it up quickly)
* Calibration of spark gaps to 0.008
* Changing gas tanks

I can get a wet puddle, but I just can't keep one. I'll have to sit on a spot for 5-10 seconds full pedal, changing the angle of torch and tungsten to metal distance to get the puddle. It seems like once it's lost, it's lost, regardless of what I do. I often will adjust my stickout, resharpen to a point and reball it, and it's easier to get it started again, but it won't last.

Is this a calibration thing, faulty component in machine, consumable issue, or user error/technique?

Comment

I am a welding repair Technician, Certified for warranty repair on every major brand out there (Miller, Lincoln, Esab, Thermal Dynamics, Thermal Arc and Hypertherm), so I know a thing or two about these machines, not everything, but you get the gist. Anyways.. I digress.. My first go to on issues like this is actually trying to rule out balance control, there have been times when the issues I had with weld quality were caused by improper balance that was caused by a component failure. I have a few questions for you regarding this and general clarifying questions:

Firstly, What is the serial number of this unit? (that's how us techs are able to search the correct schematic, parts break down, etc)

Are you able to maintain a proper puddle for DCEN TIG, or is this issue happening on AC only?

When you adjust the balance, do you see the Cleaning area widen and slim? Does it actually seem to effect the weld?

Are you using the Green (pure) Tungsten?

Have you tried ruling out the Pedal or remote, or are you in "local" control? I ask this because the pedal itself could not be sending the correct "command" signal to the machine, causing a limited output.

Try ruling our your leads if possible (put a spare tig torch on and try, or even do some stick welding to make sure it has good, controllable output)

Basically on issues like weld quality and balance you just need to start mentally slicing up this machine into individual systems, and rule out those systems and components. In welding technical training we are taught to test the 5 key systems that are essential to operation and can be found in any welder which are:

Start Signal: (the trigger on your pedal, or MIG unit, or fingertip control)

Command Signal: (the amperage or voltage set point you choose gives feedback to the boards, so that those boards know what you are "commanding")

Feedback Signal: (this is normally an amperage clamp inside the machine that gives feedback to the board, it works similarly to fuel trim on cars in the sense that if the feedback is lower than your command signal, the unit will attempt to compensate for that by increasing or decreasing output)

Synchronization signal (this would be the gate pulse from the boards, to the SCR's or IGBT's)

Input power (I think you know this one)

with those 5 signals, you can pinpoint MOST issues to being within one of those 5 systems. With what you have stated, I personally would be hooking up the unit to a scope and verifying balance is actually changing, that you actually have full rated output and it is 100% controllable, and that your leads & remote are ruled out as the issue. If all else fails, you can and should call Millers Technical support @ 920-735-4505 EXT 3, tell the lady you need to talk to a technician on a syncrowave 250, if Boon picks up tell him Logan sent you and you need Jeff Johnson for this issue and proceed from there.

P.S. If it ends up being a the amperage clamp on the inside of the machine, they are discontinued but I happen to have a stock of them, Jeff Johnson has my contact info too.

Comment

I am a welding repair Technician, Certified for warranty repair on every major brand out there (Miller, Lincoln, Esab, Thermal Dynamics, Thermal Arc and Hypertherm), so I know a thing or two about these machines, not everything, but you get the gist. Anyways.. I digress.. My first go to on issues like this is actually trying to rule out balance control, there have been times when the issues I had with weld quality were caused by improper balance that was caused by a component failure. I have a few questions for you regarding this and general clarifying questions:

Firstly, What is the serial number of this unit? (that's how us techs are able to search the correct schematic, parts break down, etc)

KE730064

Are you able to maintain a proper puddle for DCEN TIG, or is this issue happening on AC only?

No problems in DCEN

When you adjust the balance, do you see the Cleaning area widen and slim? Does it actually seem to effect the weld?

Seems to adjust, yes. See pic.

Are you using the Green (pure) Tungsten?

I've tried lots of different tungsten, mostly 2% lanthanated blue, 1.5% lanthanated gold, pure, and 2% ceriated orange. Never really noticed a big difference of one working better than another.

Have you tried ruling out the Pedal or remote, or are you in "local" control? I ask this because the pedal itself could not be sending the correct "command" signal to the machine, causing a limited output.

I use a foot pedal. Not familiar enough to try any other set up... Can I switch it to panel option for amperage control and scratch start?

Try ruling our your leads if possible (put a spare tig torch on and try, or even do some stick welding to make sure it has good, controllable output)
I've stick welded just fine with it. Torch is newer and work lead has a good clean copper braided line.

Basically on issues like weld quality and balance you just need to start mentally slicing up this machine into individual systems, and rule out those systems and components. In welding technical training we are taught to test the 5 key systems that are essential to operation and can be found in any welder which are:

Start Signal: (the trigger on your pedal, or MIG unit, or fingertip control)

Command Signal: (the amperage or voltage set point you choose gives feedback to the boards, so that those boards know what you are "commanding")

Feedback Signal: (this is normally an amperage clamp inside the machine that gives feedback to the board, it works similarly to fuel trim on cars in the sense that if the feedback is lower than your command signal, the unit will attempt to compensate for that by increasing or decreasing output)

Synchronization signal (this would be the gate pulse from the boards, to the SCR's or IGBT's)

Input power (I think you know this one)

with those 5 signals, you can pinpoint MOST issues to being within one of those 5 systems. With what you have stated, I personally would be hooking up the unit to a scope and verifying balance is actually changing, that you actually have full rated output and it is 100% controllable, and that your leads & remote are ruled out as the issue. If all else fails, you can and should call Millers Technical support @ 920-735-4505 EXT 3, tell the lady you need to talk to a technician on a syncrowave 250, if Boon picks up tell him Logan sent you and you need Jeff Johnson for this issue and proceed from there.

I never learned how to hook up to a scope (nor would know what that entails). What tools are needed for this? Is this type of diagnostic pretty typical, as in a welding supply place that does servicing would check all these things? The boss had it serviced by the mom and pop welding supply shop, but didn't find much/had replaced the spark gap parts.
Would Tech support walk me through a diagnostic test if I had the right tools?

If it ends up being a the amperage clamp on the inside of the machine, they are discontinued but I happen to have a stock of them, Jeff Johnson has my contact info too.

Comment

I know this may sound like a dumb question to ask, but is there a chance you have your torch connected to the wrong terminal? It should be connected to the negative, work clamp to the positive. In reverse things would be backwards? Just a thought? Although they are both red, the one under the gas valve is electrode, the other work clamp.
It's a uneducated guess but worth checking. Good luck.

Comment

I know this may sound like a dumb question to ask, but is there a chance you have your torch connected to the wrong terminal? It should be connected to the negative, work clamp to the positive. In reverse things would be backwards? Just a thought? Although they are both red, the one under the gas valve is electrode, the other work clamp.
It's a uneducated guess but worth checking. Good luck.

Comment

No problems in DCEN: - Good, then that largely rules out leads and the pedal is you have full controllable output and good puddle control in DCEN

I've tried lots of different tungsten, mostly 2% lanthanated blue, 1.5% lanthanated gold, pure, and 2% ceriated orange. Never really noticed a big difference of one working better than another.
----- I asked about the Pure Tungsten because that is what is recommended for Static Transformer TIG machines welding aluminum and is what I always recommend as to follow the MFG. Guidelines.

I use a foot pedal. Not familiar enough to try any other set up... Can I switch it to panel option for amperage control and scratch start?
------The pedal is likely already ruled out, because you can TIG in DCEN no problem, but yes, you can put amperage into "local" and scratch start no problem, it will go RIGHT to what you set it to though, there is no range. So if you set it to 100amps, it will weld (or should anyway) @ 100 amps as oppose to when using the pedal you are setting the MIN-MAX range which would be 0-100 with my given example.

I never learned how to hook up to a scope (nor would know what that entails). What tools are needed for this? Is this type of diagnostic pretty typical, as in a welding supply place that does servicing would check all these things? The boss had it serviced by the mom and pop welding supply shop, but didn't find much/had replaced the spark gap parts.
Would Tech support walk me through a diagnostic test if I had the right tools?
----------------A scope would be hooked up where your torch and ground hook up to, you would turn High Frequency off, Trigger the unit with the pedal or contactor switch, and then adjust the balance min to max and watch the scope. The quality and depth of troubleshooting work done largely depends on two things, the amount of labor you are willing to pay, and well the individual technician. Tech support would yes, they would likely even send you a schematic too.

At this point If it were in my shop I would want to verify it's rated output on AC, as the Polarity switch's can cause issues too if the contact pads on them start wearing or are pitted. You could be running into an issue with a switch itself that is limiting the amount of amperage that actually gets to the torch and ground, but that in DCEN those contacts are just fine. I have seen that before too, if you are able to unpanel it I would check the switch contact pads with a flashlight, the stationary pads that are in use when in "AC" would be my first priority.

P.S. based on that picture I still see quite a bit of cleaning being consistent throughout each of those tests, I still am not convinced that a balance issue is not the root of this issue, it almost looks as if it's stuck in max cleaning. When you took that picture, were you using the same exact amperage for each of those welds? If you were not, I would repeat that test with a fixed amperage, say 100-150 amps, and try it multiple times like you did with the same amperage, just adjusting the balance before each test. Good Luck!

Comment

No problems in DCEN: - Good, then that largely rules out leads and the pedal is you have full controllable output and good puddle control in DCEN

I've tried lots of different tungsten, mostly 2% lanthanated blue, 1.5% lanthanated gold, pure, and 2% ceriated orange. Never really noticed a big difference of one working better than another.
----- I asked about the Pure Tungsten because that is what is recommended for Static Transformer TIG machines welding aluminum and is what I always recommend as to follow the MFG. Guidelines.

I use a foot pedal. Not familiar enough to try any other set up... Can I switch it to panel option for amperage control and scratch start?
------The pedal is likely already ruled out, because you can TIG in DCEN no problem, but yes, you can put amperage into "local" and scratch start no problem, it will go RIGHT to what you set it to though, there is no range. So if you set it to 100amps, it will weld (or should anyway) @ 100 amps as oppose to when using the pedal you are setting the MIN-MAX range which would be 0-100 with my given example.

Didn't have a difference when scratch start method used.

I never learned how to hook up to a scope (nor would know what that entails). What tools are needed for this? Is this type of diagnostic pretty typical, as in a welding supply place that does servicing would check all these things? The boss had it serviced by the mom and pop welding supply shop, but didn't find much/had replaced the spark gap parts.
Would Tech support walk me through a diagnostic test if I had the right tools?
----------------A scope would be hooked up where your torch and ground hook up to, you would turn High Frequency off, Trigger the unit with the pedal or contactor switch, and then adjust the balance min to max and watch the scope. The quality and depth of troubleshooting work done largely depends on two things, the amount of labor you are willing to pay, and well the individual technician. Tech support would yes, they would likely even send you a schematic too.

I'll look into this.

At this point If it were in my shop I would want to verify it's rated output on AC, as the Polarity switch's can cause issues too if the contact pads on them start wearing or are pitted. You could be running into an issue with a switch itself that is limiting the amount of amperage that actually gets to the torch and ground, but that in DCEN those contacts are just fine. I have seen that before too, if you are able to unpanel it I would check the switch contact pads with a flashlight, the stationary pads that are in use when in "AC" would be my first priority.

How do you verify it's rated output? The scope? I took some sandpaper to the switch contact pads. No obstruction from what I can see...

P.S. based on that picture I still see quite a bit of cleaning being consistent throughout each of those tests, I still am not convinced that a balance issue is not the root of this issue, it almost looks as if it's stuck in max cleaning. When you took that picture, were you using the same exact amperage for each of those welds? If you were not, I would repeat that test with a fixed amperage, say 100-150 amps, and try it multiple times like you did with the same amperage, just adjusting the balance before each test. Good Luck!

Yeah, full pedal. A freshly ground tungsten tip does ball up faster when set to a lower number. Takes a bit longer for it to ball up on normally used 6.5-7.

Comment

Well, as the owner of a seldom used Syncrowave 250 I'm interested maybe more then most to discover what has gone wrong?

I'm no substitute for the expert advice you've been given, and from what I've read, I'm not sure anything I have to offer would be of much value or was besides a cursory check? But that's not enough to stop me from chiming in further.

"Yeah, full pedal. A freshly ground tungsten tip does ball up faster when set to a lower number. Takes a bit longer for it to ball up on normally used 6.5-7."

This is a clue. Question is why? Something about internet diagnostics? As it was mentioned, if the power source was in front of a guy, it would be so much easier.

I'd go back to basics. I'd disconnect what I could, so I'm left with a power source, stinger and a work clamp and try welding SMAW in DCEN,DCSP and AC. Click, click, click. Pull long arc, run some short arc, and adjust amperage up and down confirming a complete range of amperage control. All other functions off.

Thinking out loud...if it passed that test, you should be able to crank the dial, with a foot pedal connected, run it again through those paces? Remote in the on position.

I noticed in a picture you have hi frequency set to max. It doesn't need to be that high, nor should it be required. You did mention however it was previously looked at? I would turn it down. Not saying it is, but excess hi freq. can cause problems.

Sometime a bit of back history is helpful? Just curious, have to had the cover off yourself? I would as well post a serial number, and such details as if it's power factor corrected? It may not help, but again I'm not the expert?

The pictures you posted of the Aluminum spots showed lots of cleaning. How that power source does that in function with my limited knowledge about such things is limited to positive and negative values being changed, tweaked to provide more or less cleaning at the same time off setting the heat to melt. If adjustment of the balance control dial changes that, or those values, I would see it as functioning?

That said, it also appears that is where you are having such issues?

With the foot pedal disconnected, hi freq. on continuous, set low on the dial, try a few things to appease me and maybe discover a few things in the process.

1) On AC, balance at 3, 100 amps, strike an arc. Your not trying to melt anything so don't let that be a concern for the moment. Your trying to discover if that dial is doing what it's supposed to do, adjust balance of + and - values.

2) Do it again at zero, establish an arc, then again at max. The ring of cleaning should have changed as well it should be noticeable the indication of surface melting or appearance of such change occurring.

I would also suggest, electrons are flowing from the conductor to the plate, hence the sand blasting of oxides, and from the plate up, the penetration and melting. As well the melting and balling of the tungsten. Now you mention a few other things that jump out to me. One was tungsten size. Not type, size. 3/32" if memory serves. A cup size of 6. Looking at your original post, and it's listed parameters, I'm going to offer what I know best, welding knowledge.

Here's what I know.

Aluminum is highly conductive. With GTAW, It takes a lot of heat slowly built up in value initially, reduced and maintained during welding with a reduction or tailing at the end.

With a Syncrowave, that means when you hit the current, the high frequency current jumps, the electrons follow the path, depending on the amount of current flow, cleaning will occur and the tungsten heats and starts to melt.

If you use too small a tungsten when welding with a transformer rectified power source on AC, regardless of tungsten type, it won't support the current and the ball that forms as the result of all those electrons departing and collecting as the current alternates in flow, makes for a very unstable ball. Is that effect preventing you from using adequate current to achieve melting?

Also, a few terms rarely discussed are arc rectification and DC component.

At the end of the day and following with interest, take what I have to offer with a grain of salt. It could well be something has crapped out? But as the owner of one, I'm following along with interest, and hope it's nothing so serious of a problem that doesn't get easily solved.